Am I missing something? I remember this happening to me with Riverview the first time I downloaded. I also tried copying the file to the Installed Worlds folder with no success.
The world shows up under Downloads, but is nowhere to be seen in the Installed Content tab, and it doesn't show up in-game either. I reconstructed the routing data, exported the world, opened the launcher, went to 'Loads' (or whatever it's called in english, but where screenschots and exports are), selected the world and clicked on 'show file', and then double clicked on the file to install it.
